The border between the Republic and Northern Ireland runs along the ridge of Cuilcagh Mountain, the distinctive tabletop summit of Cuilcagh Mountain Park, the world's first cross-border geopark. Its lower slopes are protected peatland habitats, while the upper slopes have dramatic sweeping cliffs. The visitor centre and the park's most high-profile attraction, the Marble Arch Caves, lie over the border from Blacklion in County Fermanagh.
On the Republic side, the megalithic Cavan Burren Park is a highlight.
